CN201983881U - Cement-based temperature sensing element applicable in positive and negative temperature self-test - Google Patents
Cement-based temperature sensing element applicable in positive and negative temperature self-test Download PDFInfo
- Publication number
- CN201983881U CN201983881U CN2011200771913U CN201120077191U CN201983881U CN 201983881 U CN201983881 U CN 201983881U CN 2011200771913 U CN2011200771913 U CN 2011200771913U CN 201120077191 U CN201120077191 U CN 201120077191U CN 201983881 U CN201983881 U CN 201983881U
- Authority
- CN
- China
- Prior art keywords
- test block
- temperature
- cement
- sensing element
- electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The utility model discloses a cement-based temperature sensing element applicable in a positive and negative temperature self-test, which comprises a test block and a pair of electrodes; the test block comprises a cement-based body; the center and the periphery of the test block are provided with the electrodes; and short-cut polypropylene hydrocarbon fibers and carbon nanotubes are uniformly distributed in the cement-based body. The electrode which is arranged on the periphery of the test block is embedded on the periphery of the test block through pure cement paste. The lengths of the short-cut polypropylene hydrocarbon fibers are 10mm to 15mm, the diameters are 7+/-0.2mum, the linear resistance is 85 omega/m, and the drawing die is 175 to 215/Gpa. The test block is in a cylindrical shape, the center and the side surface of the test block are provided with the electrodes, the electrode in the center of the test block comprises a copper wire and the other electrode comprises a copper mesh which is enclosed on the side surface of the test block. The cement-based temperature sensing element applicable in the positive and negative temperature self-test measures the capacitance signals of a sensor element but not resistance signals as electrical signals for sensing the ambient temperature.
Description
Technical field
The utility model relates to the sensing element in a kind of detection technique field, particularly a kind ofly is used to monitor that the mass concrete internal temperature changes and can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself with mass concrete combines together.
Background technology
Temperature has remarkable influence and effect to the stress of large volume concrete structural, and the research of structure temperature field and internal temperature gradient occupies more and more important position in the research of modern project structure detection.The measurement of Temperature Field in Bulky Concrete is no matter be in construction period or run duration all has crucial meaning.In construction period, nearly all large volume concrete structural all will take measures to carry out temperature control, reduces thermograde in the structure, prevents that the crack from taking place, and guarantees one-piece construction safety; At run duration, temperature load is the one of the main reasons that causes dam deformation and STRESS VARIATION.Therefore, in time and exactly obtaining the temperature field information of dam concrete inside configuration, is the key of massive concrete construction control, also is one of important content of mass concrete run duration safety monitoring.
Yet, the temperature survey of mass concrete, usually need pre-buried temperature sensor to carry out temperature monitoring, it is how not enough that this brings for actual engineering operation, mainly show as: a temperature sensor is measured the temperature of a point only, wants mass concrete is carried out multimetering, needs pre-buried a plurality of temperature sensors, this stress that will cause a plurality of positions of structure reduces, and influences the permanance of xoncrete structure greatly; The environmental requirement height of this class sensor to working, poor durability, tenure of use is low, and cost is high relatively, needs continuous replacing simultaneously in the use of xoncrete structure, improves construction costs greatly; Temperature sensing modulator material and concrete material poor performance can accurately not measured the temperature of large volume concrete structural.Therefore, but invention can compatible multimetering with mass concrete not influence structure durability, long service life, cost is low and can realizes that the cement based temperature-sensing element that temperature is tested oneself seems very necessary and urgent.
The researcher finds both at home and abroad, and chopped carbon fiber is joined in the cement concrete, can give concrete good responsive to temperature characteristic.For example, clocklike reducing appears in the concrete resistivity that is mixed with an amount of carbon fiber with the rising of environment temperature, i.e. temperature resistance characteristic; An amount of carbon fiber can make concrete become semiconductor material, has Seebeck effect, specially CN200610024718 utilizes the Seebeck effect of carbon fiber reinforced concrete to make the clever concrete sensor component that temperature is tested oneself, and the temperature Centralized that this sensing element is measured is between 0 ℃～150 ℃.
The environment temperature of actual mass concrete can change in positive and negative temperature range, minimum temperature especially, and in the winter or the highlands of cold, the minimum temperature of environment can reach between-15 ℃～-20 ℃.For example, the fate of Qinghai-Tibet Platean year positive and negative alternating temperature is up to 180d, and temperature difference per day can reach 30 ℃.Therefore, research can be used for positive and negative temperature measurement, under positive subzero temperature acts on repeatedly, still have good durability to can be used for the cement based temperature-sensing element that positive subzero temperature tests oneself significant.The temperature-measuring range of present temperature-sensing element also is confined to above zero, and the resistance signal by the survey sensor element is as the electric signal of sense ambient temperature, repeatedly repeated measurement data instability.
Summary of the invention
For the temperature-measuring range that solves present temperature-sensing element also is confined to above zero, the unsettled drawback of repeated measurement data repeatedly; The utility model provides a kind of cement based temperature-sensing element that positive subzero temperature is tested oneself that can be used for.
In order to solve the problems of the technologies described above, the technical solution of the utility model is:
A kind ofly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, comprise test block and pair of electrodes, this test block comprises cement matrix, and described test block center and outer periphery have described electrode, and uniform weak point is cut polypropylene/olefin carbon fiber and carbon nano-tube in the described cement matrix.
The electrode that is positioned at described test block periphery is embedded in the test block periphery by the clean slurry of plain cement.
Described weak point is cut the polypropylene/olefin carbon fiber: length 10-15mm, diameter 7 ± 0.2 μ m, line resistance 85 Ω/m, stretch modulus 175-215/Gpa.
Described carbon nano-tube is: overall diameter 20-40nm, internal diameter 5-10nm, length 50 μ m, specific surface area 110m2/g, density 2.1g/cm3.
Described test block is cylindrical, and test block center and side are provided with described electrode, and the electrode that is positioned at the test block center comprises a copper cash, and another electrode comprises the copper mesh that is trapped among the test block side.
The utility model is by the capacitance signal of survey sensor element, but not resistance signal is as the electric signal of sense ambient temperature.This is because capacitance signal is compared with resistance signal, has the characteristics sensitive, good stability that change.That is to say, utilize the temperature-capacitance characteristic of sensor element to measure the environment temperature of xoncrete structure.Conductive fiber in the sensor element comprises chopped carbon fiber and carbon nano-tube, these conductive materials form many capacitors in cement matrix, wherein form relatively large capacitor between the carbon fiber, and form the more capacitor of microcosmic between the carbon nano-tube, thereby further strengthen the capacitance of whole temperature sensor element at microcosmos area.Rising along with temperature, more charge carrier is owing to thermal excitation participates in conduction in the element, these charge carriers make the capacitance of sensor element constantly raise owing to the existence of numerous capacitors is adsorbed, the environment temperature that the electric capacity by survey sensor can the detecting sensor component ambient.
The utility model adopts A Lite-barium-bearing calcium sulfo-aluminate cement as cement matrix, mainly based on following reason, this cement is mainly formed still similar with the Portland cement composition, has guaranteed that the matrix of temperature sensor element and large volume concrete structural have excellent compatibility; Simultaneously, the barium-bearing calcium sulfo-aluminate mineral have the microdilatancy characteristic, can reduce the porosity of temperature sensor element, guarantee that element has good frost resistance, guarantee the accuracy of measuring-signal under positive negative temperature acts on repeatedly; Compensate the drying shrinkage of cement matrix simultaneously, reduce check crack, improve the permanance of sensor element.
Because principal ingredient of the present utility model is the potpourri of A Lite-barium-bearing calcium sulfo-aluminate cement and sand, permanance is good, and has good compatibility with the large volume cement concrete.Can directly the utility model be placed in the mass concrete during use, mounting process is simple, simultaneously can be according to the requirement at the position of detecting, and the size that changes sensor is with the convenient temperature that detects required detection mass concrete position.
The beneficial effects of the utility model are: 1. adopt A Lite barium-bearing calcium sulfo-aluminate cement as cement matrix, the temperature-measuring range of temperature-sensing element is expanded to below freezing; 2. this sensing element capacitance signal is to the temperature variation sensitivity, and repeatedly repeated measurement data is stable.
Description of drawings
Below in conjunction with accompanying drawing embodiment of the present utility model is described in further detail:
Fig. 1: can be used for the cement based temperature-sensing element permittivity variation that positive subzero temperature is tested oneself at-45 ℃ of-90 ℃ of 1# and 2#.
Fig. 2: can be used for cement based temperature-sensing element that positive subzero temperature tests oneself permittivity under temperature conditions repeatedly at-45 ℃ of-90 ℃ of 2# and change.
Fig. 3: structural representation of the present utility model.
Among the figure: 1 test block, 2 first electrodes, 3 second electrodes, 4 plain cements are starched only.
Embodiment
As shown in Figure 3, can be used for the cement based temperature-sensing element that positive subzero temperature tests oneself and comprise test block 1 and pair of electrodes.Electrode comprises first electrode 2 and second electrode 3.This test block 1 comprises cement matrix, and test block 1 center is provided with first electrode 2, and the periphery is provided with second electrode 3.Uniform weak point is cut polypropylene/olefin carbon fiber and carbon nano-tube in the cement matrix.
For second electrode 3 is solidified and test block 1 periphery, second electrode 3 is embedded in test block 1 periphery by the clean slurry 4 of plain cement.
Preferably, described weak point is cut the polypropylene/olefin carbon fiber and is: length 10-15mm, diameter 7 ± 0.2 μ m, line resistance 85 Ω/m, stretch modulus 175-215/Gpa.
Preferably, described carbon nano-tube is: overall diameter 20-40nm, internal diameter 5-10nm, length 50 μ m, specific surface area 110m2/g, density 2.1g/cm3.
Preferably, described test block 1 is cylindrical, and test block 1 center and side are respectively equipped with first electrode 2 and second electrode 3.First electrode 2 comprises a copper cash, and second electrode 3 comprises the copper mesh that is trapped among the test block side.
Table 1 A Lite-barium-bearing calcium sulfo-aluminate cement performance
The short polypropylene/olefin carbon fiber performance parameter of cutting of table 2
The performance parameter of table 3 carbon nano-tube
Each ore deposit phase system ratio (wt%) of table 4 A Lite-barium-bearing calcium sulfo-aluminate cement clinker
Preparation is as the A Lite-barium-bearing calcium sulfo-aluminate cement of physicochemical property as described in table 1, table 2, table 3 and the table 4, short polypropylene/olefin carbon fiber and the carbon nano-tube of cutting.Short cut that the polypropylene/olefin carbon fiber cleans, dried, a certain proportion of weak point is cut the polypropylene/olefin carbon fiber join in the methocel solution, stir with glass bar and guarantee that the short polypropylene/olefin carbon fiber of cutting disperses fully; Simultaneously carbon nano-tube is joined in the neopelex solution and disperse, again above-mentioned two kinds of solution are poured in the agitated kettle and stirred, add entry by water cement ratio 0.35, beta-naphthalenesulfonic-acid salt water reducer (water weight 3 ‰), tbp defoamer (water weight 2 ‰), add cement then in batches and (add normal sand simultaneously, aggregate-to-cement ratio is 3: 1), after stirring 4min, injection forming in the standard mortar mould, imbed copper net electrode, jolt ramming, sample is put into standard curing room, and (temperature is 20 ± 1 ℃, relative humidity 〉=90%) maintenance, put into water behind the 1d and continue maintenance 28d, temperature-sensing element is made in vacuum drying.Wherein sand-cement slurry accounts for 98.5-99.5% in the temperature-sensing element, and weak point is cut the polypropylene/olefin carbon fiber and accounted for 0.4%-1%, and carbon nano-tube accounts for 0.1%-0.8%.Fig. 1 is a sensing element permittivity change curve in-45 ℃ of-90 ℃ of temperature ranges, repeatedly duplicate measurements, and its capacitance data is stable, and amplitude of variation is obvious.Sample raw material proportioning sees Table 5:
Table 5 sample raw material proportioning (wt%)
Fig. 1 can be used for cement based temperature-sensing element permittivity that positive subzero temperature tests oneself with the variation of temperature curve for 1# in-45 ℃ of-90 ℃ of scopes and 2#.As seen from Figure 1, the 1# element of carbon-doped nanometer tube is not obvious in the subzero capacitance variations, compare with the 2# element that mixes carbon nano-tube simultaneously, its integral capacitor changes irregular, therefore, the introducing of carbon nano-tube can make the measurement range of temperature element expand to subzero, and DATA REASONING is more regular and stable.
Fig. 2 can be used for cement based temperature-sensing element permittivity that positive subzero temperature the tests oneself change curve under temperature variation condition repeatedly for 2# in-45 ℃ of-90 ℃ of scopes.As seen from Figure 1, the temperature-capacitance curve of sample is repeatedly showing good temperature-capacitance characteristic under the temperature cycles effect, and only the 1st circulation differs bigger with other 3 round-robin temperature-capacitance curves.This be because: after the temperature cycles 1 time, sensing element inside just has part moisture and is dried, and moisture reduces in the sample, has reduced the inside of temperature-sensing element and can cause temperature-capacitance curve to descend for the amount of ions of polarization; Wherein the 1st temperature cycles sample moisture is dried at most, so its capacitance curve and differ bigger other 3 times.It can also be seen that by Fig. 1 along with the increase of cycle index, sensing element temperature-capacitance curve is linear to remain unchanged substantially, shows better repeatability.Temperature-sensing element data variation amplitude is big, and electric capacity rises with temperature and changes acumen, and data variation repeatability is strong, and is obviously regular.The introducing of carbon nano-tube has enlarged the temperature measurement range of temperature-sensing element, to subzero.
Claims (9)
1. one kind can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, comprise test block and pair of electrodes, this test block comprises cement matrix, it is characterized in that: described test block center and outer periphery have described electrode, and uniform weak point is cut polypropylene/olefin carbon fiber and carbon nano-tube in the described cement matrix.
2. according to claim 1ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: the electrode that is positioned at described test block periphery is embedded in the test block periphery by the clean slurry of plain cement.
3. according to claim 1 and 2ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described weak point is cut the polypropylene/olefin carbon fiber and is: length 10-15mm, diameter 7 ± 0.2 μ m, line resistance 85 Ω/m, stretch modulus 175-215/Gpa.
4. according to claim 1 and 2ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described carbon nano-tube is: overall diameter 20-40nm, internal diameter 5-10nm, length 50 μ m, specific surface area 110m2/g, density 2.1g/cm3.
5. according to claim 3ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described carbon nano-tube is: overall diameter 20-40nm, internal diameter 5-10nm, length 50 μ m, specific surface area 110m2/g, density 2.1g/cm3.
6. according to claim 1 and 2ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described test block is cylindrical, test block center and side are provided with described electrode, and the electrode that is positioned at the test block center comprises a copper cash, and another electrode comprises the copper mesh that is trapped among the test block side.
7. according to claim 3ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described test block is cylindrical, test block center and side are provided with described electrode, and the electrode that is positioned at the test block center comprises a copper cash, and another electrode comprises the copper mesh that is trapped among the test block side.
8. according to claim 4ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described test block is cylindrical, test block center and side are provided with described electrode, and the electrode that is positioned at the test block center comprises a copper cash, and another electrode comprises the copper mesh that is trapped among the test block side.
9. according to claim 5ly can be used for the cement based temperature-sensing element that positive subzero temperature is tested oneself, it is characterized in that: described test block is cylindrical, test block center and side are provided with described electrode, and the electrode that is positioned at the test block center comprises a copper cash, and another electrode comprises the copper mesh that is trapped among the test block side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200771913U CN201983881U (en) | 2011-03-23 | 2011-03-23 | Cement-based temperature sensing element applicable in positive and negative temperature self-test |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200771913U CN201983881U (en) | 2011-03-23 | 2011-03-23 | Cement-based temperature sensing element applicable in positive and negative temperature self-test |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201983881U true CN201983881U (en) | 2011-09-21 |
Family
ID=44611340
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011200771913U Expired - Fee Related CN201983881U (en) | 2011-03-23 | 2011-03-23 | Cement-based temperature sensing element applicable in positive and negative temperature self-test |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201983881U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108599625A (en) * | 2018-07-02 | 2018-09-28 | 浙江理工大学 | Heat preserving exterior wall surfaces externally and internally temperature difference energy collecting device |
| CN109798998A (en) * | 2019-02-22 | 2019-05-24 | 山东建筑大学 | A kind of thermocouple measurement device and method accurately fixed |
-
2011
- 2011-03-23 CN CN2011200771913U patent/CN201983881U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108599625A (en) * | 2018-07-02 | 2018-09-28 | 浙江理工大学 | Heat preserving exterior wall surfaces externally and internally temperature difference energy collecting device |
| CN108599625B (en) * | 2018-07-02 | 2023-11-14 | 浙江理工大学 | Thermal insulation external wall inner and outer surface temperature difference energy collecting device |
| CN109798998A (en) * | 2019-02-22 | 2019-05-24 | 山东建筑大学 | A kind of thermocouple measurement device and method accurately fixed |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Han et al. | A review on carbon-based self-sensing cementitious composites | |
| Zhang et al. | Effect of characteristics of assembly unit of CNT/NCB composite fillers on properties of smart cement-based materials | |
| Wen et al. | Electrical-resistance-based damage self-sensing in carbon fiber reinforced cement | |
| Azhari et al. | Carbon fiber-reinforced cementitious composites for tensile strain sensing | |
| Wen et al. | Seebeck effect in carbon fiber-reinforced cement | |
| Sun et al. | Thermoelectric percolation phenomena in carbon fiber-reinforced concrete | |
| Deng et al. | Preparation and piezoresistive properties of carbon fiber-reinforced alkali-activated fly ash/slag mortar | |
| CN101886954A (en) | Cement-based temperature sensing element for positive and negative temperature automatic measurement | |
| Zuo et al. | Sensing properties of carbon nanotube–carbon fiber/cement nanocomposites | |
| Xiao et al. | Self-monitoring properties of concrete columns with embedded cement-based strain sensors | |
| CN112268933B (en) | Concrete sensor with multiple intelligent characteristics and preparation method thereof | |
| CN201983881U (en) | Cement-based temperature sensing element applicable in positive and negative temperature self-test | |
| CN101509757A (en) | Carbon fibre conducting cement-based composite material engineering strain measuring system | |
| Hussain et al. | Study on self-monitoring of multiple cracked concrete beams with multiphase conductive materials subjected to bending | |
| CN105486218B (en) | It is a kind of to monitor the smart material strain gauge and application that bituminous pavement strains | |
| CN101050985A (en) | Local monitoring pressure sensitive cement base stress and strain sensor of concrete structure | |
| CN103232204B (en) | Sensing material, preparation method and application thereof | |
| Han et al. | Piezoresistive response extraction for smart cement-based composites/sensors | |
| CN201795880U (en) | Anti-freezing type sensor element of cement base stress | |
| Jiang et al. | Graphene nanoplatelets-based self-sensing cementitious composites | |
| CN105510405A (en) | Capacitive cement-based humidity sensitive element and preparing method thereof | |
| Wang et al. | Health monitoring of C60 smart concrete based on self-sensing | |
| YANG et al. | Dynamic performance of municipal sludge solidified soil under freeze-thaw cycle | |
| CN102506691B (en) | Cement-based intelligent composite material strain sensor with temperature compensation function | |
| Wang et al. | Influence of salt freeze-thaw cycles on the damage and the following electrical and self-sensing performance of carbon nanofibers concrete |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110921 Termination date: 20120323 |